Formulation and evaluation of 6-thioguanine-loaded gum rosin/ poly(ethylene oxide) blend microspheres for controlled release applications

Abstract

This study focuses on the design, development, and in vitro evaluation of blend microspheres composed of gum rosin (GR) and poly(ethylene oxide) (PEO) by the water-in-oil emulsion solvent evaporation method for controlled release of 6-thioguanine (6-TG), an anticancer drug. By analyzing the microspheres by Fourier transform infrared spectroscopy, the chemical interactions between the polymers and the drug were explored. The results of the DSC analysis confirmed the drug was molecularly dispersed after loading into the polymer matrix. By scanning electron microscopy (SEM), it was confirmed that the microspheres were spherical. X-ray diffraction was used to analyze the crystal structure of the drug before and after encapsulation.In vitro release studies revealed that the release rate varied with the pH of buffer media, polymer ratio, drug loading amount, and observed release rate over 18 h. In vitro release results confirm that the developed microspheres are suitable for delivery of bioactive agents at intestinal pH (7.4). Based on the results, the developed blend microspheres were found to be economically and industrially feasible by applying a systematic formulation approach.